Boltless pipe connector

ABSTRACT

A connector for a plain end pipe comprising a housing ( 7 ) for location over the pipe, an annular recess ( 4 ) formed in an inner surface of the housing ( 7 ), a seal ( 1 ) located in the recess ( 4 ), a nipple ( 8 ) for the supply of grease under pressure, and segmental grippers of L-shaped cross section comprising a leg ( 6 ) and a foot ( 5 ) having a serrated inner surface for engagement with the pipe. Such connectors have wide tolerance within a certain range of nominal pipe outside diameter.

DESCRIPTION Technical Field

The invention relates to boltless pipe connectors suitable forattachment on or adjacent the end of a plain end pipe to enable couplingof said pipe to a further pipe, pump, valve, end cap or the like. Theseconnectors are universal, that is they have a wide tolerance within acertain size range: pipes of a given nominal diameter do not all havethe same outside diameter.

EP 727026 uses grease under pressure to grip and seal pipes as they arejoined. This technology has been limited to small tolerances, typically4 or 5 mm, in pipe diameter. The maximum movement of the grippers isapproximately half thickness of the grippers or they would slip out ofthe container groove in the housing.

In the connector described and shown in the present application, a seallocated in an annular recess in an inner surface of the connector hassegmental grippers of L-shaped cross-section comprising a leg betweenthe seal and a wall of the recess, and a foot having a serrated innersurface for engagement with the pipe. This allows for a toleranceexceeding 10 or 15 mm thereby allowing the pipe connection to be usedwith all pipes of a given nominal diameter.

A metal shim may be provided between the legs of the adjacent grippers.Grippers may be provided between one or each side of the seal and anadjacent wall of the recess. The housing is provided with an inlet for asealing fluid which may be a nipple for the supply of grease or oilunder pressure or components for the formation of an epoxy resin to makethe seal permanent. The housing is generally provided with an air bleedoffset from the sealing fluid inlet for use during assembly when therecess is filled with grease or oil as sealing fluid.

DRAWINGS

FIG. 1 is a half-section of the pipe connector according to the above EP727026;

FIG. 2 is a section through a pipe connector according to one embodimentof the present invention;

FIG. 3 shows the configuration of a gripper and shim in FIG. 2; and

FIG. 4 is a sectioned end view of the pipe connector, the section beingtaken at 4—4 in FIG. 2 and revolved about the central axis.

In the prior art connector of FIG. 1, a mechanism using high pressuregrease activates a plurality of grippers. The grippers are pusheddownward onto the pipe by grease from a high pressure grease gun butcontained within the connector housing to cause a dynamic seal to pressthe arcuate segment shaped grippers onto the pipe.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 2, the connector comprises a hollow metal housing 7having an annular recess 4. In the recess 4, there is an annularpolymeric seal 1 having a concave outer surface and lateral wings insealing engagement with the inside of the recess 4. Segmental grippersof L-shaped cross-section each comprise a leg 6 contacting the seal 1through metal shims 3 and a foot 5 having a serrated inner surface forengagement with a pipe wall. As shown in FIG. 4, the metal shims 3extend across the gaps between the legs 6 of the adjacent grippers toallow relative movement therebetween on sealing.

During assembly, grease is applied at pressure through a nipple 8 tofill the recess 4. Air is allowed to escape through a bleed (not shown).On installation, more grease is applied at high pressure from a gunthrough the nipple 8 and presses the seal 1 downward so that thegrippers are brought into engagement with the pipe wall, the air bleedbeing closed at this stage.

This allows a greater tolerance in each pipe connector because the leg 6of the gripper prevents the polymer seal 1 from protruding into the gapbetween the housing 7 and the pipe wall. The grease presses downward onthe seal 1 and on its wings to ensure firm contact with housing 7. Asthe grease pressure increases, it moves the polymer seal 1 down thehousing 7 towards the pipe wall. The polymer seal 1 presses on the feet5 of the grippers to move them onto the pipe wall. The pressure of thegrease causes the feet 5 to cut into the pipe wall. The gap between thegripper feet 5 allows the polymer seal 1 to flow onto the surface of thepipe and form a seal 9 which prevents any leaks along the outer surfaceof the pipe wall.

The metal shims 3 prevent nipping of the seal 1 between the legs 6 ofthe grippers, and protruding between the edges of adjacent gripper legs6.

What is claimed is:
 1. A pipe connector for a plain end pipe comprisinga housing for location over the pipe, an annular recess formed in aninner surface of the housing to surround the pipe, a seal located in therecess, and an inlet for the supply of sealing fluid into the recessbetween the housing and the seal, characterized by segmental grippers ofL-shaped cross-section comprising a leg between the seal and a wall ofthe recess, and a foot having a serrated inner surface for engagementwith the pipe.
 2. A pipe connector according to claim 1 characterized bya metal shim between the legs of adjacent grippers.
 3. A pipe connectoraccording to claim 2 characterized by grippers between each side of theseal and an adjacent wall of the recess.
 4. A pipe connector accordingto claim 3 characterized by the inlet being a nipple for the supply ofgrease under pressure.
 5. A pipe connector according to claim 2characterized by the inlet being a nipple for the supply of grease underpressure.
 6. A pipe connector according to claim 1 characterized bygrippers between each side of the seal and an adjacent wall of therecess.
 7. A pipe connector according to claim 6 characterized by theinlet being a nipple for the supply of grease under pressure.
 8. A pipeconnector according to claim 1 characterized by the inlet being a nipplefor the supply of grease under pressure.